Octamethyltrisiloxane, also referred as MDM, can be effectively used as a solvent in electronic device cleaning systems. It is known in the art to use a Filtrol based equilibration process to equilibrate MM and a D source to give as high as possible level of MDM followed by Filtrol filtration and product distillation. The MDM content at equilibrium is low, with large quantities of MM and MD.sub.x M, x&gt;1. The MM and higher boilers can be recycled. Although eventually the overall conversion of M and D to MDM is high with recycle, the process pound per pound of product is also very high. Further, the use of Filtrol and the necessity of filtration on each pass make the overall process efficiency even lower. The manufacture flow is so complicated and time-consuming that the manufacturing cost becomes too high.
In a application Ser. No. 08/092,450 filed Jul. 15, 1993, U.S. Pat. No. 5,420,221, Applicant and his co-inventors described a novel process which is characterized as a disproportionation reaction. Applicants discovered that if two or more M and D containing polymers, which have different molecular weights, are combined at weight ratios of from about 1:99 to 99:1 or more preferably from 5:95 to 95:5 in the presence of a condensation/disproportionation catalyst, such as a linear phosphonitrilic chloride, an extremely fast and complete siloxane disproportionation reaction takes place between M and D containing polymers. The reaction results in the formation of a lower molecular weight product than one of the two starting materials without the formation of substantial amount of cyclics.
Applicant continued his research to develop a new and simple method for large production of low molecule weight siloxanes such as octamethyltrisiloxane and decamethyltetrasiloxane.